A method of modifying selected properties of polymers is to provide polarity or functionality within the polymer as by introducing maleic anhydride groups as described in U.S. Pat. Nos. 4,427,828, 4,578,429, and 4,927,889. The anhydride groups have five-membered ring structures and readily undergo hydrolysis to acid groups when contacted with water. Careful packaging and handling of the polymers is required to exclude moisture that converts the anhydride groups to acid groups. Anhydride groups are preferred over acid groups because the anhydride groups are easier to melt process and do not release water during processing.
Published European Patent Application 298,667 describes the polymerization of elastomers having blocks of alkyl esters and further describes conversion of the alkyl ester groups to acid groups. The acid groups release water during processing which limits the utility of the polymers in molding process.
International Publication No. WO 87/04810 describes homopolymers of t-butylmethacrylate which are thermally converted to polymers of methacrylic anhydride and then irradiated to form an image with a positive resist.